JP6024006B2 - Preventive or therapeutic agent for HTLV-I related myelopathy - Google Patents

Description

  The present invention relates to a preventive or therapeutic agent for HTLV-I related myelopathy (HAM). The present invention also relates to an agent for improving movement disorders associated with HAM.

  Adult T cell leukemia virus (HTLV-I) -related myelopathy (hereinafter also referred to as “HAM”) is a chronic progressive myelitis caused by infection with the human retrovirus HTLV-I. Although this disease is not a lethal disease, once it develops, it certainly causes progressive gait disturbance (finally bedridden) and urination disorder, and the ADL and QOL of patients in daily life are markedly limited. For this reason, this disease was recognized as an intractable neurological disease by the Ministry of Health, Labor and Welfare in 2008, and the establishment of an immediate treatment method is urgently required.

  Conventionally, immunomodulation therapy such as administration of corticosteroids and interferon-α has been the main treatment for HAM. This is a symptomatic treatment targeting chronic myelitis caused by HAM, and aims to improve clinical symptoms by the effect of a drug having an immunomodulating action. However, since the effects of these treatments are not satisfactory and the treatments are also long-term, various problems such as the appearance of side effects and medical costs have been pointed out (Non-patent Document 1). Although attempts have been made to improve the above problems by adjusting the dose and administration period of corticosteroids and interferon-α, or by adding vitamin C or the like, it has not been solved yet. In addition, various attempts such as plasma exchange therapy (Non-Patent Document 2) have been made as immunomodulation therapy, but they also have the same problem.

  Zidovudine + lamivudine therapy has been reported as an anti-HTLV-I therapy for HAM, but its effectiveness has not been proved by a recent case control study (Non-patent Document 3). In addition, anti-HTLV-I therapy with valproic acid, an HDAC inhibitor, has a major problem of transiently increasing the amount of peripheral blood HTLV-I provirus, which is the greatest risk factor in the pathology of HAM. I have it.

The pathogenesis of HAM is initiated by infiltration of the HTLV-I-infected cells in the spinal cord, which is markedly increased in peripheral blood. Therefore, elimination of HTLV-I-infected cells from the living body is considered to be a causal therapy for this disease, but a therapeutic method has not yet been established.
The mode of infection of HTLV-I spreads infection through cell-to-cell transmission rather than infection with free virus particles. Specifically, HTLV-I initiates cell-to-cell propagation by binding of HTLV-I coat protein gp46 to HSPG (Heparan sulfate proteoglycan), which is a target cell receptor. Therefore, preventing HTLV-I from spreading in vivo by blocking this binding and inhibiting cell-to-cell propagation of HTLV-I is one target of causal therapy.

  In this connection, heparin, one of the sulfate polysaccharides, has an inhibitory action on HTLV-I infection in in vitro tests and is clinically effective for HAM patients in in vivo tests. Has been reported by one of the inventors of the present invention (Non-Patent Documents 4 and 5). However, heparin therapy has not been put into practical use because of the necessity of daily intravenous administration by injection and the safety problem due to the strong anticoagulant action of heparin.

  As described above, no causal therapy for HAM that can withstand practical use has been found so far. In particular, with respect to movement disorders associated with HAM, various drugs that have been performed in the past with HAM treatment have not been found to have an improvement effect, which has been a major medical problem.

Nakagawa M. et al., J. Neurovirol., Vol. 2, p. 345-55 (1996) Matsuo H. et al., Lancet, vol. 2, p. 1109-13 (1986) Graham P. Taylor et al., Retrovirology, vol. 3: 63 (2006) Nagasato K. et al., J. Neurol. Sci., Vol. 115, p. 161-8 (1993) Ida H. et al., Antiviral Research, vol. 23, p. 143-59 (1994) Nakamura, Tatsufumi et al., Role of small GTPases involved in cell-to-cell spread of HTLV-I in HAM / TSP and basic study for the development of new treatment with polysulfate. Heart health science research project HTLV-I in vivo Elucidation of infection spreading mechanism and research on development of HAM therapy by its control 2008 Summary / Shared Research Report 2009. p. 26-30

  The present invention has been made in view of the above state of the art. That is, an object of the present invention is to provide a prophylactic or therapeutic agent for HAM useful for fundamental prevention and treatment of HAM, which is highly safe and can be quickly put into practical use. Another object of the present invention is to provide an agent for improving movement disorders associated with HAM.

The present inventors have intensively studied to solve the above problems.
The present inventors first focused on a mechanism that inhibits the binding of HTLV-I coat protein gp46 and HSPG, which is a target cell receptor, to inhibit HTLV-I cell-to-cell propagation. Went. As a result, it was confirmed in an in vitro experiment that polysulfate pentosan, which is one of sulfate polysaccharides, has a very strong HTLV-I infection inhibitory effect at a low dose compared to heparin (the above non-patent document). 6). Polysulfate pentosan has already been marketed for over 50 years, mainly in Europe as an antithrombotic and antihyperlipidemic drug, and in the US and Canada as an indication for the relief of pain and discomfort due to interstitial cystitis It is a drug with established safety. In Japan, clinical studies on knee osteoarthritis patients (Kumagai K. et al., BMC Clinical Pharmacology, vol. 10: 7 (2010)) and Phase I clinical studies on Japanese healthy adult men have already been conducted. It has been implemented and safety for Japanese has been confirmed. From this, it was expected that polysulfate pentosan could be a safe and effective new preventive / therapeutic agent for causative therapy for HAM. Therefore, the inventors further conducted a study of the clinical effect of polysulfate pentosan on HAM patients. As a result, in HAM patients treated with polysulfate pentosan, a tendency to decrease the amount of HTLV-I provirus in peripheral blood was observed. Furthermore, the clinical effects of improving leg spasticity and shortening walking time were significantly observed in HAM patients by treatment with polysulfate pentosan. Furthermore, as a newly discovered finding, the observed improvement effect of movement disorder does not necessarily correlate with the decrease in the amount of HTLV-I provirus, suggesting a possibility of a new mechanism of action. there were.
As a result of further studies based on such knowledge, the present inventors have completed the present invention.

That is, the present invention provides the following.
[1] A prophylactic or therapeutic agent for HTLV-I-associated myelopathy, comprising polysulfate pentosan or a pharmaceutically acceptable salt thereof as an active ingredient.
[2] The agent according to [1] above, wherein the polysulfate pentosan or a pharmaceutically acceptable salt thereof is sodium polysulfate sodium.
[3] An agent for improving lower limb movement disorders associated with HTLV-I-related myelopathy, comprising polytosulfate polytosane or a pharmaceutically acceptable salt thereof as an active ingredient.
[4] The agent according to [3] above, wherein the movement disorder is gait disorder due to spasticity or spastic paraplegia.
[5] The agent according to [4] above, wherein the movement disorder is a gait disorder due to spastic paraplegia.

The agent of the present invention can be used for the causative therapy of HAM because it can lead to the decrease of HTLV-I infected cells with the lifetime of infected cells by preventing the spread of HTLV-I infected cells in the body of the subject. Can be done. In addition to the effect of reducing HTLV-I-infected cells, clinical symptoms of HAM, particularly movement disorders of the lower limbs, can be improved, or progression thereof can be prevented. To date, various drugs that have been implemented in the treatment of HAM have not been found to have an improvement effect based on the pharmacological effects of the compounds used in the present invention, and have improved clinical symptoms of HAM or promoted its progression. It can be the first drug that can be prevented. The drug of the present invention is also highly safe because the effect is manifested at a low dose, and since the effect is obtained with a low administration frequency such as once a week, the burden on HAM patients is small, and the QOL is improved. The patient's financial burden can also be reduced. Furthermore, since the polysulfate pentosan is already marketed as a pharmaceutical for other uses, the drug of the present invention can be expected to be put to practical use at an early stage.
In addition, since the improvement effect of lower limb movement disorder by the drug of the present invention is due to a mechanism different from the reduction of the amount of HTLV-I provirus, the drug of the present invention is for the improvement of lower leg movement disorder caused by causes other than HAM. Could also be used.

It is a graph which shows the average value of a subject's amount of HTLV-I provirus about each before the treatment with polysulfate pentosan, 8 weeks after the start of treatment, and 12 weeks later. It is a graph which shows the average value of a subject's 30-m walk time about each before the treatment with polysulfate pentosan, 8 weeks after a treatment start, and 12 weeks later. At the start of treatment with polysulfate pentosan, 1st week, 2nd week, 3rd week, 4th week, 5th week, 6th week, 7th week (end of treatment), 8th week, 12th week The results of 10m walk (a), 30m walk (b), and stairway descent (c) are shown average values over the examined cases. For each of a), b), and c), the left shows the required time, and the right shows the time reduction rate.

Hereinafter, the contents of the present invention will be described in detail. Hereinafter, the preventive or therapeutic agent for HAM is referred to as the prophylactic / therapeutic agent of the present invention, and the above-mentioned improving agent for lower limb movement disorders related to HAM is referred to as the improving agent of the present invention. Moreover, these are generically called the chemical | medical agent of this invention.
As described above, the agent of the present invention has the effect of preventing or treating HAM in order to prevent the spread of HTLV-I in the body of the subject, thereby leading to a decrease in HTLV-I-infected cells. Apart from the effect of reducing the amount, it also has the effect of improving symptoms associated with HAM in the subject. That is, the distinction between the preventive / therapeutic agent and the improving agent is mainly focused on the purpose or effect of the administration of the drug of the present invention, and is not necessarily different as a product.

  The agent of the present invention contains polysulfate pentosan or a pharmaceutically acceptable salt thereof as an active ingredient.

  The polysulfate pentosan contained as an active ingredient in the drug of the present invention is a sulfated polysaccharide that is extracted from plants and semi-synthesized, and is a polysaccharide present on almost all cell surfaces and extracellular matrix of animals. Structurally similar to sulfuric acid. In addition, pentosan sodium polysulfate supplied by bene pharmaChem GmbH & Co., KG (Munich, Germany) as a pharmaceutical product can be suitably used as this drug. The structure of sodium polytosulfate sodium is shown below.

  The molecular weight of the polysulfate pentosan used in the drug of the present invention is not particularly limited as long as it is suitable for administration to a subject for the purpose of prevention / treatment of HAM or improvement of symptoms, and varies depending on the production method. Usually, it is about 4000 Da to about 6000 Da.

  The polysulfate pentosan contained as an active ingredient in the medicament of the present invention may be used in the form of a neutral molecule or in the form of a pharmaceutically acceptable salt thereof, and the salt is a base addition salt. obtain. The base forming the base addition salt may be an inorganic base or an organic base. The inorganic base is not particularly limited, and examples thereof include ammonium hydroxide, alkali metal hydroxide, alkaline earth metal hydroxide, carbonate, bicarbonate, and the like. More specifically, for example, water Examples thereof include sodium oxide, potassium hydroxide, potassium carbonate, sodium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, calcium hydroxide, calcium carbonate and the like. The organic base is not particularly limited, and examples thereof include ethanolamine, triethylamine, and tris (hydroxymethyl) aminomethane. As described above, a preferable example includes, but is not limited to, sodium polytosulfate, which is a salt of polysulfate pentosan and sodium hydroxide. These salts can be produced by a method known per se.

  As described above, polysulfate pentosan is a drug that has already been sold overseas for over 50 years, and its safety has been established. In Japan, clinical studies on knee osteoarthritis patients and phase I clinical trials for Japanese healthy adult males have already been conducted, and safety for Japanese has been confirmed. Thus, the agent of the present invention can be used safely.

  The agent of the present invention is administered to mammals (eg, humans, monkeys, horses, cows, dogs, mice, etc.), preferably humans, and used for the prevention or treatment of HTLV-I-related myelopathy or the improvement of symptoms. Can do. It is said that there are 10 to 20 million carriers of HTLV-I in the world, and prevention of HAM by the agent of the present invention can be carried out, for example, on carriers of HTLV-I that do not develop HAM. . Further, treatment of HAM or improvement of symptoms by the agent of the present invention can be performed on patients diagnosed with HAM by comprehensive judgment based on clinical symptoms, test data, etc. related to HAM, for example. In the present specification, improvement of symptoms includes not only achieving complete or partial resolution of the symptoms, but also preventing, reducing, or delaying deterioration of the symptoms.

  The symptom related to HTLV-I related myelopathy (HAM) targeted by the ameliorating agent of the present invention is not particularly limited as long as it is a symptom developed in a patient in relation to the onset of HAM. Specific examples of such symptoms include chronic inflammation of the spinal cord; movement disorders in various body parts (eg, lower limbs, hands, fingers, etc.); sensory disturbances such as numbness and pain; bladder including urination difficulty, frequent urination, and constipation Rectal disorder; lower body sweating disorder; orthostatic hypotension; impotence; mild dementia. These symptoms can be related to each other, and are not particularly limited. However, a preferable target symptom of the improving agent of the present invention is movement disorders of the lower limbs related to HAM. Examples of lower limb movement disorders related to HAM include lower limb spasticity, gait disturbance due to spastic paraplegia, and the like, which are particularly preferred target symptoms of the improving agent of the present invention.

Spasticity is a type of muscle hypertension and is due to abnormally increased muscle stretch reflexes. Clinically, spasticity is a rate-dependent resistance to stretching, defined as a condition in which muscles contract excessively due to lack of inhibition from the central nervous system, which ultimately leads to increased reflexes Is done. The Ashworth scale is well known as a method of measuring spasticity, and its modified version by Bohannon is well used clinically (modified Ashworth scale; Bohannon RW, Smith MB: Interrater reliability of a Modified Ashworth Scale of Muscle Spasticity. Phys Ther 67: 206-207, 1987). This is an index for evaluating spasticity in the following six stages.
0-No increase in muscle tone.
1-There is a slight increase in muscle tone, and there is a catch and disappearance or slight resistance at the end of the range of motion when flexing or stretching.
1+-A slight increase in muscle tone is seen, with less than half of the range of motion being caught and followed by a slight resistance.
2—Almost all of the range of motion has a more pronounced increase in muscle tone, but it is easy to move.
3- A significant increase in muscle tone is seen, making passive movement difficult.
4-Hardened and cannot be bent or stretched.

  The ameliorating agent of the present invention is administered to a patient with leg spasticity associated with HAM, for example, in the above-described modified Ashworth scale, even if there is one or more improvements or no change in the level, by an appropriate clinician It can provide significant improvements that can be observed, or can prevent, reduce or delay one or more stages of deterioration, or significant deterioration seen by an appropriate clinician without any change in stage.

On the other hand, regarding gait disturbance due to spastic paraplegia related to HAM, the gait disturbance in this specification is caused not only by an obstacle during walking, but also by an obstacle during running, ascending / descending stairs, or an obstacle in walking function. It also includes wheelchairs and bedridden states. The following motor dysfunction levels have been proposed as indicators of gait disturbance (Osame M. et al., HTLV-I-associated myelopathy (HAM) revisited. HTLV-I and the Nervous System, Alan R. Liss, Inc. , p.213-223, 1989.):
0: No abnormalities in walking and running 1: Slow running speed 2: Gait abnormality (stumbling, stiffness of knee)
3: Unable to walk 4: Handrail required to move up and down stairs 5: Walking with one hand 6: Unable to walk with one hand, more than 10m with both hands 7: Walking with both hands 5m or more, within 10m 8 : Can walk within 5 m with both hands. 9: Cannot walk with both hands, can move on all fours. 10: Can not move on all fours, can move, etc. 11: Cannot move on its own, can roll over. 12: Cannot roll over. Can not move

  The improving agent of the present invention is administered to a patient with a gait disorder due to spastic paraplegia related to HAM, for example, in the degree of motor dysfunction described above, even if there is no improvement in one stage or no change in stage Can provide significant improvement seen by a healthy clinician, or prevent, reduce, or delay one or more stages of deterioration or significant deterioration seen by an appropriate clinician, even if there is no change in stage be able to.

  The agents of the present invention can take a variety of dosage forms. Examples of the dosage form include oral preparations (eg, capsules, tablets, granules, powders, etc.), parenteral preparations (eg, injections, etc.) and the like.

  For example, in order to obtain a preparation for oral administration, according to a method known per se, the above polysulfate pentosan or a pharmaceutically acceptable salt thereof, for example, an excipient (eg, lactose, sucrose, starch, etc.), a disintegrant (eg, , Starch, calcium carbonate, etc.), binder (eg, starch, gum arabic, carboxymethylcellulose, polyvinylpyrrolidone, hydroxypropylcellulose, etc.) or lubricant (eg, talc, magnesium stearate, polyethylene glycol 6000, etc.) Then, if necessary, it can be made into an oral preparation by coating by a method known per se for the purpose of taste masking, enteric or sustained, if necessary. Examples of the coating agent include general film-forming coating agents (eg, hydroxypropylmethylcellulose, ethylcellulose, hydroxymethylcellulose, hydroxypropylcellulose, polyoxyethylene glycol, etc.), Tween 80, Pluronic F68, enteric coating agents (eg, cellulose). Acetate phthalate, hydroxypropylmethylcellulose phthalate, hydroxymethylcellulose acetate succinate, hydroxypropylmethylcellulose acetate succinate, methyl methacrylate / methacrylic acid copolymer, methyl acrylate / methacrylic acid copolymer, etc.), dye (eg, titanium oxide, bengara, Talc) is used. When performing enteric coating, it is also effective to provide one or two or more intermediate layers with the film-forming coating agent according to a method known per se between the central core containing the active ingredient and the enteric coating.

  It is also effective to administer the agent of the present invention parenterally as an injection. Examples of the injection include aqueous and non-aqueous isotonic sterile injection solutions, which may contain antioxidants, buffers, antibacterial agents, isotonic agents and the like. Aqueous and non-aqueous sterile suspensions are also included, which may contain suspending agents, solubilizers, thickeners, stabilizers, preservatives and the like. The preparation can be enclosed in a container in unit doses or multiple doses like ampoules and vials. Since the drug of the present invention can produce a high effect even if it is not administered every day, it can be suitably administered even if it is administered by injection without significantly impairing the patient's QOL.

  There are no particular limitations on the dose and interval of administration of the drug of the present invention, and it can be appropriately selected according to the purpose. Considering various factors including the patient's age, disease duration, body weight, sex, medical condition, route of administration, patient's level of metabolic / excretion function, dosage form used, active ingredient administered, etc. It can be determined by a vendor. Specifically, for example, the pharmaceutical agent of the present invention is administered at a dose of about 10 mg to about 200 mg once a day to 7 days as an active ingredient for one adult (weight 50 kg), preferably It is administered at a dose of about 25 mg to about 150 mg once every 2 days to 7 days, particularly preferably at a dose of about 50 mg to about 100 mg at a dose interval of 3 days to 7 days. As the administration results in a reduction in viral load or improvement in clinical symptoms in the subject, the amount and frequency of administration may be reduced.

  The drug of the present invention may be used in combination with other drugs, and examples of such drugs include prednisolone, corticosteroid, interferon-α, vitamin C and the like that have been conventionally administered as symptomatic treatment for HTLV-I-related myelopathy. Can be mentioned. In addition, as the effects of the drug of the present invention are obtained, it is possible to reduce or discontinue these drugs whose side effects are problematic.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

1. Clinical trial of polysulfate pentosan treatment for HTLV-I related myelopathy (HAM) patients

[Purpose of research]
A clinical study was conducted with the goal of confirming the efficacy and safety of patients with HAM by subcutaneous injection of polysulfate pentosan. The following two points were mainly targeted.
(1) Verification of therapeutic effects in terms of lower limb motor function and urination function
In an in vitro test, it has been confirmed by one of the present inventors that polysulfate pentosan has a strong HTLV-I infection inhibitory action at a lower concentration than heparin. However, no studies have been conducted so far in which the correlation between the intensity of the HTLV-I infection inhibitory action of polysulfate pentosan in HAM patients and the clinical effect has been clearly confirmed.
The main symptoms of HAM include motor / gait disorders, and the items for clinical evaluation of these symptoms include examination of lower limb motor function (walking time, stair descent time, spasticity, motor dysfunction etc.). By evaluating these items before and after administration of polysulfate pentosan, the therapeutic effect on HAM by subcutaneous injection of polysulfate pentosan was verified.
As an administration method, subcutaneous injection that can sufficiently put polysulfate pentosan into the body was used. In addition, the administration method was set with reference to the dose and administration period of polysulfate pentosan that have been confirmed to be safe for Japanese in clinical studies on knee osteoarthritis.
(2) Verification of the therapeutic effect from the aspect of virus (HTLV-I) A significant increase in the amount of HTLV-I provirus was observed in peripheral blood of HAM patients, and removal of this virus from the living body was the cause therapy. Expected to be connected. However, since a study that clearly confirmed the correlation between viral load and clinical symptoms has not been carried out, the correlation between the degree of reduction in viral load and the clinical effect was unknown.
Therefore, as a virological evaluation, peripheral blood HTLV-I provirus amount was monitored, and immunological markers that are expected to change due to the decrease in provirus were simultaneously monitored, and the effect of polysulfate pentosan on HTLV-I Verified. Simultaneously with the measurement of the viral load, the clinical effect (lower limb motor function, etc.) was also evaluated, and the correlation between the reduction of the viral load and the clinical effect was confirmed. Moreover, the amount of HTLV-I provirus before and after the administration of polysulfate pentosan was measured, the effect of polysulfate pentosan on viral load reduction was confirmed, and the possibility of being a causal therapy was verified.

〔Method〕
Location: Nagasaki University Hospital Subjects: 12 HAM patients (9 women, 3 men, age: 49-77 years, disease duration: 3-52 years) (Table 1).
Test Method: Pentosan polysulfate sodium was subcutaneously administered to the upper arm at 25 mg for the first time (week 0), 50 mg after one week, 100 mg once a week from the second week to the seventh week. As the test drug, a 1 ml ampoule of 100 mg / ml sodium pentosan polysulfate supplied from Bene AG of Germany was used.
Test items: Subjective symptoms, neurological findings (spasticity, week 0) (first administration), week 8 (first week of treatment) and week 12 (5th week of treatment). (Including walking time, stairs descent time, motor dysfunction etc.). Similarly, general laboratory tests, immunological (serum soluble IL-2 receptor (sIL-2R), peripheral blood lymphocyte blastogenesis test) and virological tests (peripheral blood HTLV-I proviral load (real-time quantitative PCR method) and anti-HTLV-I antibody titer) were also performed.
(Ethical considerations)
This clinical study was approved by the Nagasaki University Ethics Committee, and at the time of implementation, the contents of the study were fully explained and written informed consent was obtained.

  In Table 1, the degree of motor dysfunction is 0: no abnormalities in both walking and running; 1: slow running speed; 2: abnormal walking (stumble, stiffness of knees); 5: Walking with one hand is impossible; 6: Cannot walk with one hand, both hands are more than 10m; 7: Walking with both hands is more than 5m and within 10m; 8: Walking with both hands 9: Unable to walk with both hands, moveable on all fours; 10: Unable to move on all fours, can move, etc .; 11: Unmovable on its own, can roll over; 12: Unable to roll over; (See Osame M. et al., HTLV-I-associated myelopathy (HAM) revisited. HTLV-I and the Nervous System, Alan R. Liss, Inc, p.213-223, 1989. ).

[result]
No significant differences were observed in the lymphocyte blastogenesis test (Table 2), soluble IL-2 receptor (sIL-2R) test (Table 3), and anti-HTLV-I antibody test (Table 4). Regarding the HTLV-I provirus amount, although no significant difference was observed in all 12 cases at the 8th week after the start of treatment, an average decrease of about 9% was observed, and at the 5th week (12th week) after the end of the administration, There was a tendency to return to the starting dose (Table 5, FIG. 1).

  On the other hand, only the case 1 (6 to 5 at the 8th week) showed improvement in the degree of motor dysfunction described above, and no change was seen in other cases. However, time reduction was seen in most cases for 10m walk (Table 6), 30m walk (Table 7) and stairway down (Table 8), and the average value of cases examined for these items (Table 9, Figure 9). 2 and FIG. 3) also confirmed the improvement. It was particularly remarkable as a characteristic of the effect on gait disturbance, and even for patients with a long morbidity (average 24.1 years) and large motor dysfunction, improvement was seen from a very early stage after the start of treatment. It was. There was also an improvement in spasticity (Table 10). The improvement of gait function is thought to be due to the improvement of spasticity that forms the basis of spastic paraplegia. There were no adverse events associated with administration of polysulfate pentosan in any case.

  From the above, it has been found that polysulfate pentosan can also improve lower limb movement disorders due to spastic paraplegia based on the spasticity of the lower limb, which is a pathological condition of HAM, in addition to the effect of reducing the amount of provirus in HAM patients. These results suggest the potential of polysulfate pentosan as a fundamental therapy for HAM.

  The agent of the present invention can be a causative therapy for HAM because it can lead to a decrease in HTLV-I-infected cells along with the lifetime of infected cells by blocking the spread of HTLV-I in the body of the subject. In addition to the effect of reducing HTLV-I-infected cells, clinical symptoms of HAM, particularly movement disorders of the lower limbs, can be improved, or progression thereof can be prevented. To date, various drugs that have been implemented in the treatment of HAM have not been found to have an improvement effect based on the pharmacological effects of the compounds used in the present invention, and have improved clinical symptoms of HAM or promoted its progression. It can be the first drug that can be prevented. The drug of the present invention is also highly safe because the effect is manifested at a low dose, and since the effect is obtained with a low administration frequency such as once a week, the burden on HAM patients is small, and the QOL is improved. The patient's financial burden can also be reduced. Furthermore, since the polysulfate pentosan is already marketed as a pharmaceutical for other uses, the drug of the present invention can be expected to be put to practical use at an early stage.

  This application is based on Japanese Patent Application No. 2011-226209 (filing date: October 13, 2011) filed in Japan, the contents of which are incorporated in full herein.

Claims (3)

  An agent for improving lower limb movement disorders associated with HTLV-I-associated myelopathy, comprising polytosulfate pentosan or a pharmaceutically acceptable salt thereof as an active ingredient. The agent according to claim 1 , wherein the movement disorder is spasticity or a gait disorder due to spastic paraplegia. The agent according to claim 2 , wherein the movement disorder is a gait disorder due to spastic paraplegia.